Ly-49 receptor expression and functional analysis in multiple mouse strains

We present data on the strain distribution and functional characteristics of the Ly‐49 receptors A, C/I, D, and G2 on DX5+ natural killer (NK) cells. We have examined tyrosine phosphorylation of the Ly‐49 molecules, regulation of NK cytotoxic functions, and in vivo marrow rejection capability. The flow cytometry results demonstrate a diverse and complex pattern of expression of the Ly‐49 receptors in the 11 strains examined. The vast majority of NK cells express Ly‐49s, although some NK1.1+ CD3+ cells also express these receptors. The results of our functional analysis indicate that H‐2Dd was able to inhibit the function of Ly‐49G2+ NK cells, not only in B6 mice, but also by NK cells derived from several haplotypes. The examination of Ly‐49 receptor tyrosine phosphorylation, which is a biochemical measure of inhibitory function, was consistently observed in the 11 mouse strains examined. In contrast, analysis of Ly‐49D function suggests its expression appears to be more restricted and that H‐2Dd is an activating ligand for this receptor. In addition, the in vivo examination of both inhibitory (Ly‐49G2) and activating (Ly‐49D) receptors demonstrated regulatory roles of these class I binding receptors in marrow transplantation. J. Leukoc. Biol. 66: 512–520; 1999.